Question

The following case study involving a failure in fissured over-consolidated clay slope was reported by Henkel and Skempton in 1954. The failure occurred in 1952 in Jackfield, Shropshire, England. The slope profile is shown in Figure 1. The failure was a translational slide where the average depth to the failure plane was 17 ft. The ground water table was very near or at the surface. The peak strength parameters of the over-consolidated clay are: cohesion, c'= 220 psf and friction angle, φ,-25. The saturated unit weight of the soil is 145 pcf. (a) [50 marks] Perform a simple infinite slope analysis with seepage parallel to the slope to determine the factor of safety. Based on your results what can you conclude on the use of the peak strength parameters in long-term stability investigation of overconsolidated clays

Answer 1